One common theme is friendship. Their different backgrounds and personalities lead to an interesting exploration of how they become friends. Another is growth. They often grow as individuals as they interact with each other. For example, Ryoma might become more open - minded because of Kamui, and Kamui might become more disciplined under Ryoma's influence.
A common theme is the exploration of their power dynamics. Since they both have different abilities, how they use them in relation to each other is often explored. For example, one might be stronger in combat while the other is better at strategy.
One common theme is adventure. Given their characters' natures, they might go on some exciting quests together in the fanfictions. For example, exploring unknown lands or fighting against powerful enemies.
Hunnigan could be a great addition. She could provide Leon with information and support from the outside, and her presence could add some tension as she might be suspicious of Ada's motives. Another good character is Wesker. His past connection to Ada could create more drama and conflict in the story. He could be a shadowy figure trying to manipulate the situation between Leon and Ada.
There's also 'Ryoma and Kamui: A New Adventure'. This fanfiction focuses on them going on an epic journey together. They face various challenges along the way, like battling powerful enemies and solving difficult puzzles. The way their personalities interact during these trials makes for a really interesting read.
One great Marx x Kamui fanfiction could be 'The Meeting of Minds'. It delves into their unique relationship and how they might interact in different scenarios. It has a really interesting plot that shows their characters evolving together.
One common theme is the unspoken attraction between them. Their relationship in the games is full of mystery and tension, and fanfiction often delves deeper into that.
Adventure is another common theme. Many fanfictions put Leon and Sonia in situations where they have to go on quests or face challenges together. This not only gives them a chance to bond but also makes for exciting stories. For example, they might be on a mission to save their world from a great evil. In the process, their relationship deepens. Also, self - discovery can be a theme. As they interact with each other, they learn more about themselves and what they truly want in life.
One plot could be that they are paired up for a difficult mission. During the mission, they start to see each other in a new light and develop feelings. For example, Kamui Woods might be impressed by Mt Lady's strength in a tough battle situation, and Mt Lady could admire Kamui Woods' strategic thinking.
You can try fanfiction platforms like Archive of Our Own (AO3). There are often many works related to different pairings, including Takumi x Kamui. Just use the search function on the site and type in 'Takumi x Kamui' to see a list of available fanfictions.